Obesity may be a "socially transmitted disease," suggests a new study which found that social norms influence our food choices.

Researchers conducted a systematic review of several experimental studies, each of which examined whether or not providing information about other peoples' eating habits influences food intake or choices.

After examining the data, investigators found consistent evidence that social norms influence food choices.

This meta-analysis found that if participants were given information indicating that others were making low-calorie or high-calorie food choices, it significantly increased the likelihood that participants made similar choices.

Also, data indicate that social norms influence the quantity of food eaten.

Additionally, the review indicated that suggesting that others eat large portions increased food intake by the participants. There was also a strong association between eating and social identity.

"It appears that in some contexts, conforming to informational eating norms may be a way of reinforcing identity to a social group, which is in line with social identity theory," said lead investigator Eric Robinson, from the University of Liverpool in UK.

"By this social identity account, if a person's sense of self is strongly guided by their identity as a member of their local community and that community is perceived to eat healthily, then that person would be hypothesised to eat healthily in order to maintain a consistent sense of social identity," said Robinson.

The need to solidify our place in our social group is just one way investigators found social norms influence our food choices.

The analysis also revealed that the social mechanisms that influence what we decide to consume are present even when we eat alone or are at work, whether or not we are aware of it.

"Norms influence behaviour by altering the extent to which an individual perceives the behaviour in question to be beneficial to them. Human behaviour can be guided by a perceived group norm, even when people have little or no motivation to please other people," said Robinson.



"Given that in some studies the participants did not believe that their behaviour was influenced by the informational eating norms, it seems that participants may not have been consciously considering the norm information when making food choices," said Robinson.

The study was published in the Journal of the Academy of Nutrition and Dietetics.